2. If the product has reached the level of intellectual property protection and applied for intellectual property protection, of course, the problem you mentioned definitely exists. In this case, you can first find out how long the term of intellectual property rights is (invention patent 10 years, utility model patent 5 years, the specific situation needs to be verified, you have applied in advance for several years), and then consider how long the supply cooperation contract should be signed.
3. When signing the cooperation contract, you can clearly put forward this question, and ask how long (say, three years) after the cooperation can obtain the intellectual property rights of the products in the form of a supplementary agreement, thus throwing the problems mentioned in 1 and 2 points to the other party, and taking the initiative in your own hands.